Colostomy rates and survival for patients with rectal cancer

Patients with rectal cancer who underwent surgery at high-volume hospitals are less likely to have a permanent colostomy, and have better survival, than those treated in low-volume hospitals, find researchers from North America.

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Postoperative mortality after some cancer surgery is inversely related to the number of operations performed at a hospital.

In this study, researchers assessed whether hospital volume influenced colostomy rates and survival for patients with rectal cancer. The team examined a large representative cohort identified from the California Cancer Registry.

The team's results are published in the latest issue of the Journal of the National Cancer Institute.

The researchers identified 7257 patients with stage I to III rectal cancer who underwent surgical resection. Patients were diagnosed between 1994 and 1997.

They linked registry data with hospital discharge abstracts and ZIP-code-level data from the 1990 US Census.

The team assessed the associations of hospital volume with permanent colostomy and 30-day mortality using the Mantel-Haenszel trend test and logistic regression.

In addition, overall survival was examined with the Kaplan-Meier method, and a multivariable Cox proportional hazards model.

The team adjusted multivariable analyses for demographic and clinical variables, and for patient clustering within hospitals.

All tests of statistical significance were 2-sided.

The researchers found unadjusted analyses across decreasing quartiles of hospital volume showed significant increases in colostomy rates (30%, 32%, 35%, and 37%). This trend was also observed for 30-day postoperative mortality (2%, 2%, 3%, and 5%). In addition, the team identified a decrease in 2-year survival (84%, 83%, 81%, and 77%).

The team determined the adjusted risks of permanent colostomy (OR = 1.37), 30-day mortality (OR = 2.64), and 2-year mortality (hazard ratio = 1.28) were greater for patients at hospitals in the lowest volume quartile, compared to in the highest volume quartile.

They found that stratification by tumor stage and comorbidity index did not appreciably affect the results.

Dr David Hodgson's team concluded, "Rectal cancer patients who underwent surgery at high-volume hospitals were less likely to have a permanent colostomy and had better survival rates than those treated in low-volume hospitals".

"Identifying processes of care that contribute to these differences may improve patients' outcomes in all hospitals".